The Influence of Muscle Fiber Typology on the Pacing Strategy of 200-m Freestyle Swimmers
in International Journal of Sports Physiology and PerformancePurpose: To determine the influence of muscle fiber typology (MFT) on the pacing strategy of elite swimmers competing in the 200-m freestyle event. Method: The top 3 career-best performances from 25 elite 200-m freestyle swimmers were analyzed—12 women (1:58.0 [0:01.3] min:s) and 13 men (1:48.4 [0:02.5]). Muscle carnosine concentration was quantified by proton magnetic resonance spectroscopy in the gastrocnemius and soleus muscles and expressed as a carnosine aggregate z score (CAZ score) relative to an age- and gender-matched nonathlete control group to estimate MFT. Linear regression models were employed to examine the influence of MFT on the percentage of overall race time spent in each 50-m lap. Results: Swimmers with a higher CAZ score spent a greater percentage of race time in lap 3 compared with swimmers with a lower CAZ score (0.1%, 0.0% to 0.2%; mean, 90% confidence interval, P = .02). For every 1% increase in the percentage of race time spent in lap 1, the percentage of race time spent in lap 3 decreased by 0.4% for swimmers with a higher CAZ score (0.2% to −0.5%, P = .00, r = −.51), but not for swimmers with a lower CAZ score (−0.1%, −0.3% to 0.1%, P = .28, r = −.18). The percentage of race time spent in lap 4 decreased by 0.8% for higher-CAZ-score swimmers (−0.5% to −1.0%, P = .00, r = −.66) and by 0.9% for lower-CAZ-score swimmers (−0.6% to −1.3%, P = .00, r = −.65) when lap 1 percentage increased by 1%. Conclusion: MFT may influence the pacing strategy of swimmers in the 200-m freestyle event, which provides an avenue for maximizing individualized pacing strategies of elite swimmers.
Mallett, Bellinger, and Minahan are with Griffith Sports Science, Griffith University, Gold Coast, QLD, Australia; Mallett is also with the School of Allied Health Sciences at the university. Mallett, Bellinger, and McGibbon are with the Queensland Academy of Sport, Nathan, QLD, Australia. Derave and Lievens are with the Dept of Movement and Sports Sciences, Ghent University, Ghent, Belgium. Kennedy and Rice are with Qscan Radiology, Gold Coast, QLD, Australia.
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